It's no secret the Cubs are banking on stardom for rookies Starlin Castro, Tyler Colvin and Andrew Cashner, a threesome that may have helped general manager Jim Hendry get one more year to turn the team around.

All three have shown signs of being future All-Stars, and Castro has a chance to win the National League Rookie of the Year award if he finishes strong offensively.

But all three also have gone through the usual growing pains that accompany young players, and how they adjust in 2011 could have a large say in the future of the franchise.

Here's a progress report on "C-cubed" heading into the final 16 games of the season:

Castro: A recent two-game benching for a mental error and a hip injury that sidelined him for the Cardinals series has dropped Castro out of the batting race because he doesn't have enough at-bats to qualify. He is hitting .312 and could finish among the top five if he can stay healthy enough to play the rest of the way.

Castro has the biggest upside of the three and his .353 average since July 10 ranks sixth in baseball. But he's also second among NL shortstops with 25 errors and continues to have concentration lapses on routine plays. Manager Mike Quade said the Cubs would like Castro to play some winter ball in the Dominican Republic, even if he doesn't pick up a bat.

Castro has the range and arm to become a top-notch shortstop, so the Cubs believe his defense will catch up to his offense in time.

Colvin: Though he has hit only two home runs since Aug. 14, including the go-ahead, three-run shot Wednesday night against Chris Carpenter, Colvin remains the Cubs' only left-handed power hitter with one home run every 17.8 at-bats. If he had enough at-bats to qualify, that would rank Colvin ninth in the league in home run frequency.

Colvin is tied with the Marlins' Mike Stanton for most home runs by a rookie (20), but he doesn't consider himself a home run hitter, like Stanton.

"It'll be exciting to get there and watch him hit," Colvin said of the upcoming series. "I think I'm going to go watch him take BP."

Colvin needs to improve his .202 average with runners in scoring position but looks more comfortable batting fifth or sixth than leadoff.

Cashner: The flame-throwing relief pitcher perhaps has progressed more than any other player since Quade took over. Cashner has a 1.54 ERA in 11 appearances under Quade and seems to have regained his Texas swagger.

"Quade has a lot of confidence in me," he said. "So did Lou (Piniella), but I have been more relaxed and just challenge guys."

Sean Marshall has mentored Cashner, much like Greg Maddux mentored Marshall, and it's paying off. On Monday, Cashner struck out Albert Pujols on a slider, a pitch he needs to be excellent to complement his 98 mph fastball.

"It was a great feeling," he said. "He's one of the best hitters in the game. Last time I got him out, he flew out to the warning track."

It was but one moment in a relatively meaningless game but a big step for Cashner.